Artificial horizon devices have been used extensively in private, commercial and military applications to assist in the manual navigation of vehicles. However, these devices have drawbacks. Typically, these devices have been placed on the control panel in a discrete location within the central field of vision for the operator. Given the space constraints on the control panel, horizon devices have been limited in size; often no more than a few inches across. The limited size makes them difficult to see and requires that the pilot focus directly on the horizon device to obtain visual information.
Further, known horizon devices have typically been units that float in a liquid such that as the plane shifts, gravity pulls the unit to the horizontal (e.g. a gimbal) or utilized mechanical gyroscopes (e.g. spinning gyroscopes). These types of devices are limited in that they do not provide an output that may be used by secondary devices in the vehicle.
Combination devices strapped down to the vehicle, including accelerometers and gyroscopes, utilize complicated algorithms to de-convolute the cross-correlated sensor signals that result from such a device. Further, these device require the pressure and temperature control of the sensors to provide accurate measurements.
Artificial horizons have also been cost prohibitive for wide adoption.